I found the correct method to fix the bug that the x96-max-plus(s905x3) gigabit ethernet does not work:
Up to now, only HK1Box/vontar x3 is the only s905x3 TV box that can be used perfectly in armbian. So I extracted the bootloader of hk1box and wrote it into x96-max-plus, and it worked.
This method is very simple, so it is recommended to everyone in need.
Step 1: upload three dtbs into /boot/dtb/amlogic :
meson-sm1-x96-max-plus-100m.dtb
meson-sm1-x96-max-plus.dtb
meson-sm1-hk1box-vontar-x3.dtb (Similar to meson-sm1-x96-max-plus.dtb, only the modal name is changed)
Step 2: modify /boot/uEnv.txt, replace dtb with meson-sm1-x96-max-plus-100m.dtb, restart the Armbian system
Step 3: upload hk1box-bootloader.img to /tmp
Step 4: Run these commands under the shell:
dd if=/tmp/hk1box-bootloader.img of=/dev/mmcblk2 bs=1 count=442
dd if=/tmp/hk1box-bootloader.img of=/dev/mmcblk2 bs=512 skip=1 seek=1
sync
reboot
Step 5: modify /boot/uEnv.txt, replace dtb with meson-sm1-x96-max-plus.dtb, and restart again.
